processors: intel or amd - pentuim or athlon, celron etc.?"
Doesn't make a great deal of difference, avoid Celeron though because of the reduced floating point performance.
What about AMD Duron processors? does PD perform ok on them? I had a computer with a Duron 600mhz and i was pretty happy with it considering the price i paid. They are really cheap. I didnt use PD on that computer so i am not sure how it would behave.